We propose to study the possible conversion of some widely used psychotropic drugs, upon interaction with nitrites (of dietary, environmental or salivary origin), into potential tumor inducing nitrosamines, which may be implicated in human cancer. This investigation will involve two stages: 1) the isolation of the nitrosation products of the drugs upon reaction with nitrites: those containing secondary or cyclic amines (nortriptyline, methylphenidate, chlordiazepoxide and others), yielding potentially carcinogenic nitrosamino derivatives, and those containing tertiary amines (imipramine, amitriptyline, chlorpromazine), from which the carcinogenic dimethylnitrosamine will result. The nitrosamino derivatives will be isolated by chromatography or by gas chromatography and mass spectra. 2) A direct test of the cancer producing ability in animals of nitrosated psychotropic drugs will be carried out. In addition, the carcinogenic effect of the simultaneous administration of nitrites and psychotropic drugs containing secondary or tertiary amines will be determined in animals. These assays for carcinogenicity will include direct, transplacental and postnatal effects. The results will indicate the degree to which some psychotropic drugs may represent a carcinogenic risk to patients and their offspring.